Common Names

Synonyms

Biostatus and Distribution

This distinctive adventive mealybug comes from Australia. It has also been found in California, USA. It lives on trees in two genera of the family Araucariaceae, Agathis and Araucaria, but it has not been found on New Zealand Kauri, Agathis australis.

Conservation status: This Adventive mealybug is found trees cultivated and naturalised trees in the genera Agathis and Araucaria.

Life Stages and Annual Cycle

Golden mealybugs have a typical mealybug life cycle. After mating the adult female lays eggs into a wax covered sac that extends from under her abdomen out the back of her body. The eggs hatch into tiny nymphs that after feeding moult into other feeding nymphal stages. The adult female emerges from the third instar nymph. The male has two nymphal stages that are followed by two non-feeding stages in white wax cocoons. The winged adult male emerges and looks for and mates with a female. There may be more than one generation per year.

The adult female is deep purple, with tufts of golden wax down midline and around margins of upper side of the body. The body is broadly oval to spherical and about 2-4 mm long. On the underside it has a pair of antennae and three pairs of legs. Also on the underside of the head is a rostrum that holds the stylets used for feeding. After mating the female lays eggs under the rear of her abdomen. The eggs are a dark purplish grey and accumulate under a layer of white flocculent wax that varies greatly in its thickness. The wax may have a base of golden wax.

First instar (stage) nymphs hatch from the eggs and crawl out of the egg sac. Like the adult, the nymph has antennae, legs and a rostrum. The first instar nymph is dark purple and has tufts of white wax on its body and a short wax tube at the end of the abdomen for excretion. When the first instar is fully grown it moults to the second instar. During moulting the nymphs skin splits in the front and it pulls its body out. The second instar nymph is similar in shape, but has tufts of golden wax like the adult female. The third and final female nymphal stage is like the second, but larger.

The male only has two nymphal instars. It is followed by two non-feeding stages, the prepupa and pupa. When the second instar male is fully grown, it moults into a prepupa which produces a flocculent white wax cocoon. Several males may make cocoons close to each other. The pupa has long wing buds and does not have walking legs. The adult male emerges from the pupa and its wings (1 pair) expand and harden. It also grows a pair of wax tails. It is presumed that the wax tails help balance the insect in flight. The adult male does not have a rostrum or stylets and does not feed. The male may mate with females of the same colony or fly to another colony to mate.

Feeding and honeydew.Mealybug adult females and nymphs have sucking mouthparts. Specially shaped rods called stylets are held in the short sheath-like rostrum. When it wishes to feed, the mealybug moves the tip of the rostrum onto the surface of the plant leaf or stem. The stylets are then gradually pushed into the plant and manoeuvred into the phloem (nutrient transport vessels) of the plant. The mealybugs suck the plant’s sap, which is high in sugars and low in other nutrients. Mealybugs excrete the excess sugary liquid, which is called honeydew, through a short white wax anal tube.

Walking, flying and dispersal.The adult male has legs and one pair of wings. It can walk around the stems where its cocoon was and it can fly to other stems or to different trees. Adult females and nymphs also have legs and can walk. They may move about the group of stems where they were born. In other insects with a none flying adult female, the first stage larvae or nymphs are able to disperse to new trees. They usually do this using the wind. It is likely that some first instar nymphs climb to a prominent place on a leaf or branch and await a gust of wind.

Recognition

The Golden mealybug is the only species of mealybug in New Zealand found on cultivated and naturalised species of Agathis and Araucaria (Araucariaceae). No species of mealybugs have been found on New Zealand Kauri, Agathis australis.

Female Golden mealybugs are deep purple, with tufts of golden wax down midline and around margins of dorsum, body broadly oval to spherical. Female egg sacs are sometimes covered with white wax and males make cocoons of white wax.

Felted pine scale, Eriococcus araucariae (Eriococcidae) is found on Araucaria species and produces sacs of white, brittle wax that may be confused with Golden scale.

Natural Enemies

No pathogens of the Golden mealybug, Nipaecoccus aurilanatus, are known.

ParasitoidsAdults of five species of wasps (Hymenoptera) have been reared from Golden mealybug in New Zealand.

PredatorsThree predators of have been recorded feeding on Golden mealybug. Two are ladybirds and the other a lacewing. The commonest species in Auckland is the Mealybug ladybird, Cryptolaemus montrouzieri.

Host Plants

The Golden mealybug is only found a cultivated and naturalised trees in the family Araucariaceae. Even though it breeds on Australian species of Agathis, it does not live on New Zealand Kauri, Agathis australis.

Feeding and honeydew.Mealybug adult females and nymphs have sucking mouthparts. Specially shaped rods called stylets are held in the short sheath-like rostrum. When it wishes to feed, the mealybug moves the tip of the rostrum onto the surface of the plant leaf or stem. The stylets are then gradually pushed into the plant and manoeuvred into the phloem (nutrient transport vessels) of the plant. The mealybugs suck the plant’s sap, which is high in sugars and low in other nutrients. Mealybugs excrete the excess sugary liquid, which is called honeydew, through a short white wax anal tube.